WO2023127304A1

WO2023127304A1 - High-frequency circuit

Info

Publication number: WO2023127304A1
Application number: PCT/JP2022/041106
Authority: WO
Inventors: Takehiro Kishida; Atsuhiro Yamamoto
Original assignee: Furuno Electric Co., Ltd.
Priority date: 2021-12-27
Filing date: 2022-11-04
Publication date: 2023-07-06
Also published as: JP2023096198A

Abstract

A high-frequency circuit (10) with multiple types of transmission lines is disclosed. A signal conductor (201) is formed in a first layer, extends into a first direction, and constitutes a microstripline (21) that transmits the high-frequency signal. A first flat film conductor (200) is formed in a second layer parallel to the first layer and extends from the position corresponding to one end of the first direction of the signal conductor (201) to the first direction. A first flat film conductor (200) is formed in a third layer running parallel to the second layer. A post-wall waveguide is formed between the first and second flat film conductor (200, 202) to transmit a high-frequency signal. The first matching conductor (301) is formed in the first layer, consists of the length of (1+2N)/4 (N is an integer) wavelengths of the high-frequency signal.

Description

HIGH-FREQUENCY CIRCUIT

The present disclosure relates generally to a high-frequency circuit, and more particularly to the high-frequency circuit with different types of transmission lines.

Background

Microstriplines are often used as transmission lines for high-frequency signals. Since microstriplines are generally formed on a dielectric substrate, and they can be formed on the same dielectric substrate as a post-wall waveguide.

A conventional microstrip is disclosed in the Japanese Patent Application, JP 2003289201 A, filed by Anritsu Corp, which describes a post-wall waveguide and junction conversion structure for a cavity waveguide. The one end of the post-wall waveguide is blocked by a through-conductor array, a first resonator, including a coupling window for jointing the one end to a cavity waveguide, and a second resonator jointed to the first resonator are formed with predetermined space by narrowing an H-plane of the post-wall waveguide in predetermined space and a waveguide bandpass filter with two sections is configured, and a broadband or desired passband is obtained.

Another conventional microstrip is disclosed in the Japanese Patent, JP 5702418 B, filed by Fujikura Ltd, which describes a mode converter having a flexible board; a ground conductor layer formed on the front and rear faces of the flexible board; a connecting part formed on the front face side of the flexible board; micropores formed from the front face of the flexible board to the desired depth; and pins, composed of a conductor filled in the micropores, connected to the connecting part. The mode converter is a miniaturized one, particularly thinned, and has a bending resistance corresponding to the thinning.

In the above prior arts, the microstriplines are often used as transmission lines for high-frequency signals. Since microstriplines are generally formed on a dielectric substrate, they can be formed on the same dielectric substrate as a post-wall waveguide. Thus, connecting the microstriplines of one transmission mode with the post-wall waveguides of different transmission mode results in transmission loss.

The microstriplines and post-wall waveguides have different transmission modes. Therefore, even if a microstripline is simply connected to a post-wall waveguide, the connecting part will be inconsistent, resulting in greater transmission loss of the high-frequency signal.

Therefore, a need exists for a high-frequency circuit that can transmit a high-frequency signal between a microstripline and a post-wall waveguide with low loss.

Summary

In order to solve the foregoing problem and to provide other advantages, one aspect of the present disclosure is to provide a high-frequency circuit. The high-frequency circuit includes a signal conductor, a first flat film conductor, a second flat film conductor, and a first matching conductor. The signal conductor of microstripline, wherein the signal conductor is is formed in a first layer, extends into a first direction, and carries high-frequency signals. A first flat film conductor is formed in a second layer parallel to the first layer and extending from the position corresponding to the signal conductor in the first direction. A second flat film conductor is formed in a third layer parallel to the second layer. A post-wall waveguide is formed between the first flat film conductor and the second flat film conductor, for transmitting the high-frequency signal. A first matching conductor consists of a length of (1+2N)/4 wavelengths (N is an integer) of the high-frequency signal formed in the first layer and connects to another end of the signal conductor and extends to the first direction. The high-frequency circuit can carry the high-frequency signal between the microstripline and the post-wall waveguide with low loss. The high-frequency signal amplification circuit can suppress the undesired radiation of the high-power high-frequency signal and transmit the high-power high-frequency signal with low loss.

In an aspect, the high-frequency circuit further includes pair of second via conductors proximate to the one end of the first matching conductor, and proximate to the inside of a post wall of the post-wall waveguide. There is a plurality of pairs of second via conductors.

In an aspect, the high-frequency circuit further includes a dielectric arranged between the first layer, the second layer, and the third layer. The post-wall waveguide has a plurality of first via conductors that extends into a lamination direction of the first, second and third layers and connects to the first flat film conductor and the second flat film conductor. Further, the plurality of first via conductors for waveguides consists of a blind via which is not exposed from the end face perpendicular to the lamination direction.

In an aspect, a width of the signal conductor and a width of the first matching conductor in the high-frequency circuit are different.

In an aspect, the high-frequency circuit further includes a second matching conductor connected to the first matching conductor and extending in a lamination direction from the first layer to the second layer.

In an aspect, the high-frequency circuit further includes a plurality of additional first via conductors. The additional first via conductors are formed in the microstripline.

In an aspect, the high-frequency circuit further includes a conductor pattern and a mounted electronic component arranged on the post-wall waveguide.

In an aspect, the high-frequency circuit further includes two microstriplines and the post-wall waveguide. The two microstriplines and the post-wall waveguide are connected using a conversion part. The conversion part is placed for each of the two microstriplines. Further, the two microstriplines and the post-wall waveguide together form a distributor.

In an aspect, the high-frequency circuit further includes an amplifier element connected to the microstripline.

In an aspect, the high-frequency circuit, further includes a laminate formed by stacking a first dielectric layer and a second dielectric layer of a flat plate, wherein the laminate has a first principal side and a second principal side. The conductor pattern and the mounted electronic component can be placed on the first principal side with high degrees of freedom. As a result, the high-frequency circuit allows for more high-density mounting and a smaller plane area.

In an aspect, the high-frequency circuit, further includes a third matching conductor. The third matching conductor is positioned between the first matching conductor and the second flat film conductor in the lamination direction of the laminate. The second and third matching conductors function as electrical walls. Therefore, by setting the shapes of second matching conductor and the third matching conductor correspondingly, impedance matching between microstripline and post-wall waveguide is achieved. This allows high-frequency circuit to transmit the high-frequency signal between the microstripline and the post-wall waveguide with even lower loss.

An advantage of various embodiments of the present disclosure is to provide a high-frequency circuit that can transmit a high-frequency signal between a microstripline and a post-wall waveguide with low loss. In the present disclosure, as the transmission mode of the high-frequency signal is different between the microstripline and the post-wall waveguide, a conversion part is used in the high-frequency circuit. The conversion part reduces the transmission loss when the high-frequency signal is transmitted between the microstripline and the post-wall waveguide.

The high-frequency circuit can transmit the high-frequency signal at low loss in the connecting part between the multiple microstriplines and the post-wall waveguide, even in a configuration with a functional circuit configuration such as a distributor, rather than a simple transmission line of the high-frequency signal. High-frequency circuit also allows for more high-density mounting and smaller plane areas.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

In the present disclosure, an open stub is formed by the first matching conductor. Thus, at the one end of the microstripline, an electrical wall is formed by the open stub, and the microstripline and post-wall waveguide are tightly coupled. Therefore, the high-frequency circuit of the present disclosure can transmit the high-frequency signal between the microstripline and the post-wall waveguide with low loss.

The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiment of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

The diagrams are for illustration only, which thus is not a limitation of the present disclosure. Moreover, those skilled in the art will understand that the drawings are not to scale.
FIG. 1 illustrates a perspective view of a high-frequency circuit, in accordance with an embodiment of the invention; FIG. 2 illustrates an exploded perspective view of the high-frequency circuit of FIG. 1, in accordance with the embodiment of the invention; FIG. 3A illustrates a plane view of the high-frequency circuit of FIG. 1, in accordance with the embodiment of the invention;FIG. 3B and FIG. 3C collectively illustrate side-section views of the high-frequency circuit of FIG. 1, in accordance with the embodiment of the invention; FIG. 4 illustrates a graph showing the S-parameters of the high-frequency circuit of FIG. 1, in accordance with the embodiment of the invention; FIG. 5A illustrates a plane view of the high-frequency circuit, in accordance with another embodiment of the invention;FIG. 5B and FIG. 5C collectively illustrate side-section views of the high-frequency circuit of FIG. 5A, in accordance with another embodiment of the invention; FIG. 6 illustrates a graph showing the S-parameters of the high-frequency circuit of FIG. 5A, in accordance with another embodiment of the invention; FIG. 7A illustrates a plane view of the high-frequency circuit, in accordance with another embodiment of the invention;FIG. 7C illustrates a side-section view of the high-frequency circuit of FIG. 7A, in accordance with another embodiment of the invention; FIG. 8A illustrates a plane view of the high-frequency, in accordance with another embodiment of the invention;FIG. 8B illustrates a side-section view of the high-frequency circuit of FIG. 8A, in accordance with another embodiment of the invention; FIG. 9 illustrates a plane view of the high-frequency circuit, in accordance with another embodiment of the invention; and FIG. 10 illustrates a schematic diagram of an exemplary high-frequency amplification circuit, in accordance with another embodiment of the invention.

Detailed description

The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that embodiments of the present disclosure may be practiced without some of these specific details.

An embodiment of the present disclosure depicting a high-frequency circuit 10 is described with reference to FIG. 1, FIG. 2, and FIG. 3. FIG. 1 illustrates a perspective view of a high-frequency circuit, in accordance with an embodiment of the invention. FIG. 2 illustrates an exploded perspective view of the high-frequency circuit of FIG. 1, in accordance with the embodiment of the invention. FIG. 3A illustrates a plane view of the high-frequency circuit of FIG. 1, in accordance with the embodiment of the invention. FIG. 3B and FIG. 3C collectively illustrate side-section views of the high-frequency circuit of FIG. 1, in accordance with the embodiment of the invention. FIG. 3B shows a section view at B-B of FIG. 3A and FIG. 3C shows a section view at C-C of FIG. 3A.

As shown in FIG. 1, FIG. 2, FIG. 3A, FIG. 3B, and FIG. 3C, the high-frequency circuit 10 includes a signal conductor 201, a first flat film conductor 200, a second flat film conductor 202, a plurality of first via conductors 221, a first matching conductor 301, a plurality of second via conductors (matching via conductors) 302 and a laminate 90.

The laminate 90 is formed mainly by a dielectric. For example, as shown in FIG. 2, the laminate 90 is formed by stacking a first dielectric layer 91 and a second dielectric layer 92 of a flat plate, respectively.

The laminate 90 has a first principal side 901 and a second principal side 902, at both ends of the thickness direction (of the z axial direction in FIG. 2). As shown in FIG. 2, the surface of the contact surface and the opposite side with the second dielectric layer 92 in the first dielectric layer 91 are the first principal side 901 of the laminate 90, and the surface of the contact surface and the opposite side with the first dielectric layer 91 in the second dielectric layer 92 are the second principal side 902 of the laminate 90. The contact surface between the first and second dielectric layers 91 and 92 is a boundary surface 910.

The signal conductor 201 is shaped to have a predetermined width (see, the length of the z- y-axial direction in FIG. 2) and extends to the transmission direction (x-axial direction of FIG. 2). The direction of +x in the x axial direction corresponds to the "first direction" of the high-frequency signal of the present disclosure. The signal conductor 201 is formed on the first principal side 901 of the laminate 90.

The first flat film conductor 200 is formed on the second principal side 902 of the laminate 90. The first flat film conductor 200 is formed almost entirely on the second principal side 902. The second flat film conductor 202 is formed on the boundary surface 910 of the laminate 90. In plane view of the laminate 90 (see, the z-axial direction in FIG. 2), the second flat film conductor 202 is formed on the opposite side with reference to one end 201E of the signal conductor 201. The width of the second flat film conductor 202 is larger than the width of the signal conductor 201 (the length of the z-y-axial direction in FIG. 2).

With such a configuration, the laminate 90 has a first layer where the signal conductor 201 is placed. In a second layer of laminate 90, the second flat film conductor 202 is placed, and in third layer of laminate 90, the first flat film conductor 200 is placed. Then, the laminate 90 is equipped with a configuration in which the first layer, the second layer, and the third layer are arranged in the lamination direction of the laminate 90 from the first principal side 901 side toward the second principal side 902.

The plurality of first via conductors 221 is columnar conductors that extend in a lamination direction. The plurality of first via conductors 221 is plane viewed and positioned to overlap the first and second

flat film conductors

200 and 202. Further, the plurality of first via conductors 221 is placed at prescribed intervals along the transmission direction of the high-frequency signal.

The plurality of first via conductors 221 forms two rows along the transmission direction of the high-frequency signal. The plurality of first via conductors 221 forms more than two columns in the y-axial direction (as shown in FIG. 2), perpendicular to the transmission direction and the lamination direction of the high-frequency signal with a prescribed interval open. In addition, two rows are arranged with the formation position of the signal conductor 201 between them in the x-axial direction, as shown in FIG. 2.

The one end of the extended direction of the plurality of first via conductors 221 connects to the first flat film conductor 200, and the other end of the extended direction connects to the second flat film conductor 202.

With the above configuration, the signal conductor 201 and the first flat film conductor 200 face each other across the first dielectric layer 91 and the second dielectric layer 92. With the above-mentioned arrangement as shown in FIG. 1 and FIG. 2, a microstripline 21 is formed.

The first flat film conductor 200 and the second flat film conductor 202 face each other across the second dielectric layer 92 and are connected by the plurality of first via conductors 221 consisting of two rows. This forms a waveguide surrounded by the first flat film conductor 200, the second flat film conductor 202, and the plurality of first via conductor 221. Therefore, these parts constitute the post-wall waveguide 22.

The distance between the signal conductor 201 and the first flat film conductor 200 in the microstripline 21 is set based on the impedance at the frequency of the high-frequency signal transmitted by the high-frequency circuit 10. Also, the distance between the first flat film conductor 200 and the second flat film conductor 202 in the post-wall waveguide 22 and the distance between two rows of a plurality of additional first via conductors 211 are set based on the transmission mode at the frequency of the high-frequencyhigh-frequency signal transmitted in the high-frequency circuit 10.

Thus, the high-frequency circuit 10 is equipped with the microstripline 21 and the post-wall waveguide 22. The microstripline 21 and the post-wall waveguide 22 are connected at one end 201E of the signal conductor 201.

As the transmission mode of the high-frequency signal is different between the microstripline 21 and the post-wall waveguide 22, a conversion part 30 is used in the high-frequency circuit 10. This reduces the transmission loss when the high-frequency signal is transmitted between the microstripline 21 and the post-wall waveguide 22.

The conversion part 30 has the first matching conductor 301 and the plurality of second via conductors 302. The first matching conductor 301 is formed on the first principal side 901. That is, the first matching conductor 301 is placed in the first layer.

The first matching conductor 301 extends from one end 201E of signal conductor 201 to the opposite side with signal conductor 201. The length of the first matching conductor 301 is 1/4 of the wavelength of the high-frequency signal transmitted by the high-frequency circuit 10. The end 201E has the signal conductor 201 at one side and first matching conductor 301 at the other side. The width of the first matching conductor 301 differs from that of the signal conductor 201 and is narrower than that of the signal conductor 201.

With this configuration, the first matching conductor 301 acts as an open stub for the high-frequency signal. This creates an open stub electrical wall (short) at the end where microstripline 21 connects to the post-wall waveguide 22. Therefore, the electromagnetic coupling between the microstripline 21 and the post-wall waveguide 22 becomes strong. As a result, the high-frequency circuit 10 can transmit the high-frequency signal between microstripline 21 and post-wall waveguide 22 with low loss.

In the above explanation, the length of the first matching conductor 301 was set at 1/4 of the wavelength of the high-frequency signal transmitted by the high-frequency circuit 10. However, the length of the first matching conductor 301, where N is an integer greater than or equal to 0, can have a similar effect by making (1+2N)/4 of the wavelength. However, it is preferable that the first matching conductor 301 is as short as possible to the extent that the above conditions are satisfied.

The plurality of second via conductors 302 is columnar conductors extending in lamination direction and is positioned to overlap the first and second

flat film conductors

200 and 202. The plurality of second via conductors 302 is placed at prescribed intervals along the transmission direction of the high-frequency signal. Further, the plurality of second via conductors 302 is placed near or proximate to the one end of the first matching conductor 301 in the transmission direction of the high-frequency signal, see, x-axial direction in FIG. 2.

The plurality of second via conductors 302 forms two rows along the transmission direction of the high-frequency signal. The two columns of the plurality of second via conductors 302 are placed with a width direction (y-axial direction in FIG. 2) perpendicular to the transmission direction and lamination direction of the high-frequency signal with a prescribed interval open. In addition, these two rows are arranged with the formation position of the signal conductor 201 between them in the width direction (see, y-axial direction in FIG. 2).

The first column (upper column in FIG. 3A) of the plurality of second via conductors 302 is arranged (arrayed) in width direction (see, y-axial direction in FIG. 3A), in parallel with the plurality of first via conductors 221. The first column of the plurality of second via conductors 302 is positioned between the post wall of the post-wall waveguide 22 and the placement positions of the signal conductor 201 and the first matching conductor 301. Similarly, the second column (lower column in FIG. 3A) of the plurality of second via conductors 302 is arranged (arrayed) in a width direction (y-axial direction in FIG. 3A) in parallel with the plurality of first via conductors 221. The second column of the plurality of second via conductors 302 is positioned between the post wall of the post-wall waveguide 22 and the placement positions of the signal conductor 201 and the first matching conductor 301.

More concrete, the first column of the plurality of second via conductors 302 is placed in the 2/3 area on the side of the plurality of first via conductors 221 between the first column of the plurality of first via conductors 221 and the first matching conductor 301. More preferably, the first column of the plurality of second via conductors 302 is located in the 1/2 area on the plurality of first via conductors 221 side between the first column of the plurality of first via conductors 221 and the first matching conductor 301. Similarly, the second column of the plurality of second via conductors 302 is placed in the 2/3 area on the side of the plurality of first via conductors 221 between the second column of the plurality of first via conductors 221 and the first matching conductor 301. More preferably, the second column of the plurality of second via conductors 302 is located in the 1/2 area on the plurality of first via conductors 221 side between the second column of the plurality of first via conductors 221 and the first matching conductor 301.

One end of the extended direction of the plurality of second via conductors 302 connects to the first flat film conductor 200.

The plurality of second via conductors 302 placed in such positions function as inductors. Therefore, the impedance matching between microstripline 21 and post-wall waveguide 22 is achieved by setting the shape, number and arrangement pattern of the plurality of second via conductors 302 correspondingly. This allows the high-frequency circuit 10 to transmit the high-frequency signal between microstripline 21 and post-wall waveguide 22 with even lower loss.

In the above explanation, the case of transmitting the high-frequency signal from microstripline 21 to post-wall waveguide 22 was explained. However, when the high-frequency signal is transmitted from the post-wall waveguide 22 to the microstripline 21, the same principle allows the high-frequency signal to be transmitted with low loss.

FIG. 4 illustrates a graph showing the S-parameters of the high-frequency circuit of FIG. 1, in accordance with the embodiment of the invention. In FIG. 4, the solid line indicates S21 (passing characteristics) and the dashed line indicates S11 (reflective properties). The high-frequency circuit 10 is designed to carry high-frequency signals in the 9.4 GHz band.

As shown in FIG. 4, with the above configuration, the high-frequency circuit 10 can make the S21, i.e., passing characteristics near 0 dB in the 9.4 GHz band and can greatly attenuate the S11, i.e., reflective properties. That is, the high-frequency circuit 10 can transmit high-frequency signals in the 9.4 GHz band with low loss in the connecting part between the microstripline 21 and the post-wall waveguide 22.

In high-frequency circuit 10, in the connecting part between the signal conductor 201 and the first matching conductor 301, the width of the conductor pattern continuously decreases from the signal conductor 201 to the first matching conductor 301. However, the shape may be such that the width of the conductor pattern decreases in steps from the signal conductor 201 to the first matching conductor 301.

The high-frequency circuit 10A related to another embodiment of the present disclosure will be described with reference to FIG. 5 and FIG. 6. FIG. 5A illustrates a plane view of the high-frequency circuit, in accordance with another embodiment of the invention. FIG. 5B and FIG. 5C collectively illustrate side-section views of the high-frequency circuit of FIG. 5A, in accordance with another embodiment of the invention. FIG. 5B shows a cross section at B-B section of FIG. 5A and FIG. 5C shows a cross-section at C-C section of FIG. 5A.

As shown in FIG. 5A, FIG. 5B and FIG. 5C, the high-frequency circuit 10A differs from the high-frequency circuit 10 of FIG. 1, in that it has a conversion part 30A. The other configuration of the high-frequency circuit 10A is the same as that of the high-frequency circuit 10, and a description of similar parts is omitted.

The conversion part 30A of FIG. 5A differs from the conversion part 30 of FIG. 1, in that second matching conductor 303 and third matching conductor 304 were added. The other configuration of the conversion part 30A is the same as that of the conversion part 30, and the description of similar parts is omitted. The conversion part 30A has a second matching conductor 303 and a third matching conductor 304 along with the first matching conductor 301.

The second matching conductor 303 is a via conductor and is formed in the second dielectric layer 92. The second matching conductor 303 is placed in the plane view of the laminate 90 at a position overlapping the first matching conductor 301. The one end of second matching conductor 303 is connected to the first matching conductor 301.

The third matching conductor 304 is a flat film conductor. The third matching conductor 304 has a predetermined shape when viewed in plane view (rectangular in the case of FIG. 5A). The third matching conductor 304 is positioned between the first matching conductor 301 and the second flat film conductor 202 in the lamination direction of the laminate 90. The third matching conductor 304 has no contact with the second flat film conductor 202. The third matching conductor 304 is connected to the other end of the second matching conductor 303.

The second and

third matching conductors

303 and 304 constitute additional matching conductors. Such second and

third matching conductors

303 and 304 function as electrical walls. Therefore, by setting the shapes of the second matching conductor 303 and the third matching conductor 304 correspondingly, impedance matching between microstripline 21 and post-wall waveguide 22 is achieved. This allows high-frequency circuit 10A to transmit the high-frequency signal between the microstripline 21 and the post-wall waveguide 22 with an even lower loss.

High-frequency circuit 10A also provides a greater variety of impedance matching than high-frequency circuit 10 by having the second matching conductor 303 and the third matching conductor 304. This allows high-frequency circuit 10A to more reliably transmit high-frequency signals between the microstripline 21 and the post-wall waveguide 22 with lower loss.

FIG. 6 illustrates a graph showing the S-parameters of the high-frequency circuit of FIG. 5A, in accordance with another embodiment of the invention. In FIG. 6, the solid line indicates S21 (i.e., passing characteristics) and the dashed line indicates S11 (i.e., reflective properties). The high-frequency circuit 10A is designed to carry a high-frequency signal in the 9.4 GHz band.

As shown in FIG. 6, the high-frequency circuit 10A, with the above configuration, can make S21 (i.e., passing characteristics) near 0 dB in the 9.4 GHz band and can greatly attenuate S11 (i.e., reflective properties). That is, high-frequency circuit 10A can transmit high-frequency signals in the 9.4 GHz band with low loss in the connecting part between the microstripline 21 and the post-wall waveguide 22.

FIG. 7A illustrates a plane view of the high-frequency circuit, in accordance with another embodiment of the invention. FIG. 7C illustrates a side-section view of the high-frequency circuit of FIG. 7A, in accordance with another embodiment of the invention. FIG. 7A is a plane view of the high-frequency circuit 10B, FIG. 7C is a side-section view of the high-frequency circuit 10B and FIG. 7C shows the C-C cross-section of FIG. 7A.

As shown in FIG. 7A and FIG. 7C, the high-frequency circuit 10B differs from the high-frequency circuit 10 of FIG. 1, in that, it has the plurality of additional first via conductors 211. The other configuration of the high-frequency circuit 10B is the same as that of the high-frequency circuit 10, and a description of similar parts is omitted.

High-frequency circuit 10B has the plurality of additional first via conductors 211. The plurality of additional first via conductors 211 is formed in the region of microstripline 21 in the high-frequency circuit 10B.

The plurality of additional first via conductors 211 is columnar conductors extending in the lamination direction. The plurality of additional first via conductors 211 is plane viewed and positioned to overlap the first flat film conductor 200. The plurality of additional first via conductors 211 is placed at prescribed intervals along the transmission direction of the high-frequency signal.

The plurality of additional first via conductors 211 forms two rows along the transmission direction of the high-frequency signal. The columns of the plurality of additional first via conductors 211 are placed along the y-axial direction as shown in FIG. 7A, and perpendicular to the transmission direction and lamination direction of the high-frequency signal with a prescribed interval open. The two rows of the plurality of additional first via conductors 211 are arranged along the x-axial direction as shown in FIG. 7A.

One end of the extended direction of the plurality of additional first via conductors 211 connects to the first flat film conductor 200. The other end of the extended direction of the plurality of additional first via conductors 211 reaches the first principal side 901.

With such a configuration, the high-frequency circuit 10B can have the same effect as the high-frequency circuit 10 and suppresses the undesired radiation of electromagnetic waves from the microstripline 21 to the side.

FIG. 8A illustrates a plane view of the high-frequency, in accordance with another embodiment of the invention. FIG. 8B illustrates a side-section view of the high-frequency circuit of FIG. 8A, in accordance with another embodiment of the invention. FIG. 8A is a plane view of the high-frequency circuit, and FIG. 8B is a side-section view of the high-frequency circuit at cross-section B-B of FIG. 8A.

As shown in FIG. 8A and FIG. 8B, the high-frequency circuit 10C of one another embodiment differs from the high-frequency circuit 10 of FIG. 1, in that, it has a conductor pattern 41 and a mounted electronic component 42. The other configuration of the high-frequency circuit 10C is the same as that of the high-frequency circuit 10, and a description of similar parts is not provided again for the sake of brevity.

High-frequency circuit 10C has the conductor pattern 41 and the mounted electronic component 42. The conductor pattern 41 is formed on the first principal side 901 of the laminate 90. The mounted electronic component 42 is placed on the first principal side 901 and implemented in the conductor pattern 41. The conductor pattern 41 and the mounted electronic component 42 are placed in the post-wall waveguide 22 area with a plane view of the laminate 90.

The first flat film conductor 200 is placed on the second principal side 902 of the laminate 90, and the second flat film conductor 202 is placed in the middle of the lamination direction of the laminate 90. Thus, the first flat film conductor 200 and second flat film conductor 202 are not exposed on the first principal side 901.

The plurality of first via conductors 221 is formed between the first flat film conductor 200 and the second flat film conductor 202. Thus, the plurality of first via conductors 221 is not exposed to the first principal side 901. That is, the plurality of first via conductors 221 are blind vias that are not exposed to the first principal side 901 (invisible from the outside of the first principal side 901).

As a result, in the region overlapping the post-wall waveguide 22 in the first principal side 901 of the laminate 90, there is no conductor constituting the post-wall waveguide 22. Therefore, the conductor pattern 41 and the mounted electronic component 42 can be placed on the first principal side 901 with high degrees of freedom. As a result, the high-frequency circuit 10C allows for more high-density mounting and a smaller plane area.

In particular, the post-wall waveguide 22 is wider when transmitting X-band high-frequency signals.

Thus, when post-wall waveguide 22 is exposed on the first principal side 901, the plane area of the high-frequency circuit 10C is enlarged. However, by having the above configuration, the high-frequency circuit 10C can effectively utilize the area of the post-wall waveguide 22 even if the plane area is large to achieve high-density mounting. Thus, the high-frequency circuit 10C, which includes mounted electronic component 42, results in a smaller plane area.

FIG. 9 illustrates a plane view of the high-frequency circuit, in accordance with another embodiment of the invention. As shown in FIG. 9, the high-frequency circuit 10D is a distributor with the structure of the high-frequency circuit 10B of FIG. 7A and the structure of the high-frequency circuit 10C of FIG. 8A. Only the differences between the high-frequency circuit 10D and the high-

frequency circuits

10B and 10C of FIG. 5A and FIG. 7A are discussed below for the sake of brevity. High-frequency circuit 10D has two microstriplines 21 and a post-wall waveguide 22D forming a distributor. The two microstriplines 21 and the post-wall waveguide 22D are connected by a conversion part 30. The conversion part 30 is placed between the two microstriplines 21.

The conductor pattern 41 and the multiple mounted electronic components 42 are placed in the area of the post-wall waveguide 22D forming the distributor with a plane view of the laminate 90D.

Thus, the high-frequency circuit 10D can transmit the high-frequency signal at low loss in the connecting part between the multiple microstriplines 21 and the post-wall waveguide 22D, even in a configuration with a functional circuit configuration such as a distributor, rather than a simple transmission line of the high-frequency signal. High-frequency circuit 10D also allows for more high-density mounting and smaller plane areas.

It should be noted that the shape, number, and placement position of the plurality of the second via conductors 302 and the shapes and placement positions of the second and

third matching conductors

303 and 304 are not limited to those described above in each of the above-mentioned embodiments. They can be set correspondingly to accommodate the required impedance matching. In addition, the configurations of the above-mentioned embodiments can be combined as appropriate.

The high-frequency circuit consisting of the above configuration can be applied to, for example, a high-frequency signal amplification circuit. FIG. 10 illustrates a schematic diagram of an exemplary high-frequency amplification circuit, in accordance with another embodiment of the invention. In FIG. 10, the thin connection lines (transmission lines) are composed of microstriplines, and the thick connection lines (transmission lines) are composed of post-wall waveguides.

As shown in FIG. 10, the high-frequency signal amplification circuit 80 includes a first amplifier 811, a second amplifier 812, a third amplifier 813, a set of amplifiers 814, a bandpass filter 82, a distributor 83, a synthesizer 84, a first waveguide 861, a second waveguide 85, and a third waveguide 862. The high-frequency signal amplification circuit 80 also has an input port 801 and an output port 802.

The input port 801 is connected to the first amplifier 811. The first amplifier 811, the bandpass filter 82 and the second amplifier 812 are connected in series. Then, as shown in FIG. 10, the second amplifier 812 is connected to the third amplifier 813 through the first waveguide 861, the second waveguide 85 and the third waveguide 862. The third amplifier 813 is then connected to the distributor 83. The distributor 83 is connected to the set of amplifiers 814, the synthesizer 84 and finally to the output port 802.

The high-frequency signal is input into the input port 801 of high-frequency signal amplification circuit 80. The first amplifier 811 amplifies the high-frequency signal and outputs it to the bandpass filter 82.

The bandpass filter 82 passes the input high-frequency signal through the frequency band, which is output as the high-frequency signal amplification circuit 80, and performs filtering to attenuate the other frequency bands. The bandpass filter 82 outputs the filtered high-frequency signal to the second amplifier 812.

The second amplifier 812 amplifies the high-frequency signal from the bandpass filter 82 and outputs it to the first waveguide 861. The first waveguide 861, the second waveguide 85, and the third waveguide 862 transmits high-frequency signals to third amplifier 813. The third amplifier 813 amplifies the high-frequency signal from the third waveguide 862 and outputs it to the distributor 83.

The distributor 83 (or divider see, DIV in FIG. 10) distributes the input high-frequency signals and outputs them to the set of amplifiers 814. The set of amplifiers 814 each amplifies the input high-frequency signal and outputs it to the synthesizer 84. The synthesizer (CMB) 84 synthesizes the high-frequency signals from the set of amplifiers 814 and outputs them to the output port 802.

Thus, the high-frequency signal amplification circuit 80 constitutes a four-stage amplification circuit in the transmission direction of the high-frequency signal. This allows the high-frequency signal amplification circuit 80 to amplify the high-frequency signal at high gain as a whole, thus constituting a so-called high-power amplifier.

In this example, the high-frequency signal amplification circuit 80 is composed of four stages of amplification circuit. However, the number of stages constituting the high-frequency signal amplification circuit 80 is not limited to four stages. The number of amplifiers connected in parallel to each stage is not limited to the configuration described above.

In one embodiment of the invention, the second waveguide 85 consists of a post-wall waveguide, and first waveguide 861 and the third waveguide 862 consist of a microstripline. Also, the bandpass filter 82, the distributor 83, and the synthesizer 84 are made up of post-wall waveguides. The first amplifier 811, the second amplifier 812, third amplifier 813, and the set of amplifiers 814 are made up of mounted electronic component and implemented in microstriplines.

In such a configuration, for example, the configuration of the high-frequency circuit described above (for example, high-frequency circuit 10 of FIG. 1) is applied to the part consisting of the second waveguide 85 and the first waveguide 861. The configuration of the high-frequency circuit described above is not limited to the part including of the second waveguide 85 and the first waveguide 861, but can also be applied to the part consisting of the second waveguide 85 and the third waveguide 862, and other parts where the microstripline and post-wall waveguide are connected.

Then, the high-frequency signal amplification circuit 80 can suppress the undesired radiation of the high-power high-frequency signal and transmit the high-power high-frequency signal with low loss by applying the post-wall waveguide and applying the configuration of the high-frequency circuit described above to the configuration in which the post-wall waveguide and the microstripline are connected.

Claims

A high-frequency circuit (10), comprising:
　　　　a signal conductor (201) of a microstripline (21), wherein the signal conductor (201) is formed in a first layer and extends into a first direction to carry a high-frequency signal;
　　　　a first flat film conductor (200) formed in a second layer parallel to the first layer and extending to the first direction from a position corresponding to one end of the signal conductor (201) in the first direction;
　　　　a second flat film conductor (202) formed in a third layer parallel to the second layer;
　　　　a post-wall waveguide formed between the first flat film conductor (200) and the second flat film conductor (202), for transmitting the high-frequency signal; and
　　　　a first matching conductor (301) having a length of a (1 + 2N)/4 wavelength of the high-frequency signal, where N is an integer, wherein the first matching conductor (301) is formed in the first layer, connects to another end of the signal conductor (201) and extends to the first direction.
The high-frequency circuit (10) according to claim 1, further comprising a pair of second via conductors (302) proximate to the one end of the first matching conductor (301), and proximate to the inside of a post wall of the post-wall waveguide.
The high-frequency circuit (10) according to claim 2, further comprising a plurality of pairs of second via conductors (302).
The high-frequency circuit (10) according to any of claims 1 to 3, further comprising a dielectric arranged between the first layer, the second layer and the third layer; wherein:
　　　　the post-wall waveguide (22) has a plurality of first via conductors (221) that extends into a lamination direction of the first, second and third layers and connects to the first flat film conductor (200) and the second flat film conductor (202), and
　　　　the plurality of first via conductors (221) comprises a blind via.
The high-frequency circuit (10) according to any of claims 1 to 4, wherein a width of the signal conductor (201) and a width of the first matching conductor (301) are different.
The high-frequency circuit (10) according to any of claims 1 to 5, further comprising a second matching conductor (303) connected to the first matching conductor (301) and extending in a lamination direction from the first layer to the second layer.
The high-frequency circuit (10) according to any of claims 1 to 6, further comprising a plurality of additional first via conductors (211), the plurality of additional first via conductors (211) is formed in the microstripline (21).
The high-frequency circuit (10) according to any of claims 1 to 7, further comprising a conductor pattern (41) and a mounted electronic component (42) arranged on the post-wall waveguide (22).
The high-frequency circuit (10) according to any of claims 1 to 8, further comprising two microstriplines (21) and the post-wall waveguide (22D).
The high-frequency circuit (10) of claim 9, wherein the two microstriplines (21) and the post-wall waveguide (22D) are connected using a conversion part (30).
The high-frequency circuit (10) of claim 10, wherein the conversion part (30) is placed for each of the two microstriplines (21).
The high-frequency circuit (10) of claim 10, wherein the two microstriplines (21) and the post-wall waveguide (22D) together form a distributor.
The high-frequency circuit (10) according to any of claims 1 to 8, further comprising an amplifier element connected to the microstripline (21).
The high-frequency circuit (10) according to any of claims 1 to 9, further comprising a laminate (90) formed by stacking a first dielectric layer (91) and a second dielectric layer (92) of a flat plate, wherein the laminate has a first principal side (901) and a second principal side (902).
The high-frequency circuit (10) according to claim 14, further comprising a third matching conductor (304), the third matching conductor (304) being positioned between the first matching conductor (301) and the second flat film conductor (202) in the lamination direction of the laminate (90).